Exeter Flood Defence Scheme
Exeter, Devon, UK (along the River Exe, from Cowley Bridge to Bridge Road, Countess Wear) · Upgrades between 2014 and 2023 (Phase 1: 2014-2016; Phase 2: 2016-2021; minor upgrades 2021-2023) · £30 million (total cost, with £6 million from government growth funding, £3 million each from Exeter City Council and Devon County Council, remainder from flood defence grant in aid)
The judgement call
Account action unavailableThe scheme was initiated due to studies indicating existing defences would not protect vulnerable parts of the city in more extreme floods. - The project demonstrates a multi-phased approach, with Phase 1 focusing on immediate risk reduction and Phase 2 on broader city-wide protection. - Significant partnership funding from various government and local entities. - Emphasis on environmental enhancements alongside flood protection, including fish passes and wetland creation. - The Exwick Radial gates automatically divert excess water, showcasing adaptive management.
Key engineering challenges
Upgrading existing flood defences (originally built in the 1960s-70s) to protect against more extreme flood events. - Deepening the Trews flood relief channel and lowering its side spill weir to increase flow capacity. - Constructing new flood walls, flood gates, control structures, and bespoke demountable defences within an urban environment. - Mitigating environmental impact through habitat creation (wetlands, tree planting) and biodiversity improvements.
Project facts
- Client / owner
- Environment Agency; Exeter City Council; Devon County Council
- Lead contractor
- —
- Lead designers
- —
- Project type
- upgrade | refurbishment
- Scale
- Reduces flood risk to more than 3,000 homes and businesses; spans over eight kilometres along the River Exe; increased system capacity from 700m³/s to nearly 900m³/s; includes raised embankments and walls, 14 flood gates, demountable barriers, and control structures; two fish passes built.
- Disciplines
- civil; hydraulic; environmental; geotechnical
- Standards & frameworks
- Designed to raise protection standard from 1-in-40 year to 1-in-80 year flood event (with a goal of less than 1% chance in any given year).
Sources: "Exeter flood defence scheme", GOV.UK, 2022, https://www.gov.uk/government/publications/exeter-flood-defence-scheme/exeter-flood-defence-scheme - "Exeter braces for winter floods as defences upgrade and warning systems enhance", What's On In Exeter, 2025, https://www.whatsoninexeter.com/exeter-braces-for-winter-floods-as-defences-upgrade-and-warning-systems-enhance/ - "Ecology mitigation works, Exeter flood defence scheme", Thomson Environmental Consultants, https://www.thomsonec.com/projects/ecology-mitigation-works-exeter-flood-defence-scheme/ - "Cowley Bridge Jn – Demountable Flood Defence", The PWI, https://www.thepwi.org/wp-content/uploads/2021/05/21-April-12-Drainage-at-Cowley-Bridge-Junction-Exeter-Mark-Howells.pdf